Alma, his brethren, and his sons “were astonished beyond all measure,” and with reason. Although Antionum was nominally part of the Nephite political hegemony, it was far separated from what Alma and his companions knew to be the core of Nephite religion and, therefore, politics.
The fact that each person said the same prayer allowed them to declare their solidarity with others who offered the prayer. It was less a devotion to God than devotion to a particular community. There is no way to know if Mormon’s conclusion in verse 23, that the Zoramites spoke no more of God until the next gathering day, was in Alma’s record or not. It could have been, or Mormon could have added it as his own summary of their lack of true devotion to God. Regardless, the Zoramite religious practices were constructed to show a devotion to others of the same believing community, rather than to God, or to specific religious principles.